Height might give clue to increased cancer risks

Taller people are at increased risk of a wide range of cancers, according to an article published online in The Lancet Oncology.

In women, the risk of cancer rises by about 16 percent for every 4 inches increase in height.

Previous studies have shown a link between height and cancer risk, but this research extends the findings to more cancers and for women with differing lifestyles and economic backgrounds

The results suggest that increases in the height of populations over the course of the 20th century might explain some of the changes in cancer incidence over time.

To investigate the impact of height on overall and site-specific cancer risk, Jane Green from the University of Oxford in Great Britain and colleagues assessed the association between height, other factors relevant for cancer, and cancer incidence in the “Million Women Study,” which included 1.3 million middle-aged women in the United Kingdom enrolled between 1996 and 2001. During an average follow-up time of about 10 years, 97 000 cases of cancer were identified.

The risk of total cancer increased with increasing height, as did the risk of many different types of cancer, including cancers of the breast, ovary, womb, bowel, leukemia and malignant melanoma.

The authors also conducted a meta-analysis, combining their results with those from 10 previous studies.

“We showed that the link between greater height and increased total cancer risk is similar across many different populations from Asia, Australasia, Europe, and North America,” explained Green, lead author of the study.

“The link between height and cancer risk seems to be common to many different types of cancer and in different people; suggesting that there may be a basic common mechanism, perhaps acting early in peoples' lives, when they are growing.”

Although it is still not clear how height is linked to increased cancer risk, height is determined by environmental influences including diet and infections in childhood, as well as growth hormone levels and genetic factors.

The authors conclude: “Of course, people cannot change their height. Being taller has been linked to a lower risk of other conditions, such as heart disease. The importance of our findings is that they may help us to understand how cancers develop.”